<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <body>
    <script>
    // 输入 1, 2, 3, 4
    // 输出：10
      function useArguments() {
        var sum = 0;
        for (var i in arguments) {
          sum = sum + arguments[i];
        }
        return sum;
      }
      console.log(useArguments(1, 2, 3, 4));
    </script>
  </body>
</html>
